There is interest in materials that can store and release hydrogen [1]. In particular, there is interest in developing liquid materials that can produce fuel-cell grade hydrogen (H2) for automotive applications. Liquid materials that release hydrogen are expected to be more readily adaptable than solids to our current liquid-based fuel infrastructure.
A material of particular interest for hydrogen storage is ammonia borane because ammonia borane has a high hydrogen storage capacity of about 19 weight percent H2 and reasonable hydrogen release kinetics [2]. Ammonia borane, however, is a solid at room temperature. Therefore, researchers have tried to prepare liquid compositions that contain ammonia borane and undergo thermal decomposition to form hydrogen (H2) and a liquid reaction product. For example, there have been attempts at preparing such liquid materials by combining ammonia borane with ionic liquids [3]. Such mixtures are indeed liquids. However, as hydrogen is released from these liquid materials, a phase change from liquid to solid has always been the result.
Liquid compositions that include ammonia borane and undergo thermal decomposition to form H2 and a liquid reaction product are desirable compositions.